Revista Ingeniería Biomédica

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In vivo swine kidney viscoelasticity during acute gradual decrease in renal blood flow: pilot study
(2014-05-05) Amador, C. (Carolina); Urban, M. (Matthew); Kinnick, R. (Randall); Greenleaf, J. (James); Shigao Chen
Métodos de imágenes de elasticidad se han utilizado para estudiar las propiedades mecánicas renales y han demostrado que el módulo elástico de los riñones del aumenta con el estado de enfermedades renales. Sin embargo, estudios en cerdos sugieren que el riñón módulo elástico también se ve afectada por las variables hemodinámicas. Un método emergente llamado Shearwave Dispersion Ultrasound Vibrometry (SDUV) ofrece una herramienta para determinar la elasticidad y la viscosidad renal. El propósito de este estudio se dirige a la evaluación de la viabilidad de SDUV para mediciones las propiedades viscoelasticas del riñón saludable durante variación aguda del flujo sanguíneo renal. En este estudio el método SDUV se realizó en un grupo de 5 riñones porcinos normales al inicio del flujo sanguíneo renal (RBF) basal y 25, 50, 75 y 100% de disminución en el RBF. El módulo elástico basal fue de 7,04 ± 0,92 kPa y 3,48 ± 0,20 kPa a 100% de disminución del RBF. La viscosidad no cambió entre el momento basal (2,23 ± 0,33 Pa • s) y el 100% de disminución del RBF (2,03 ± 0,32 Pa • s). Los datos de este estudio indican que variables tales como el flujo local de sangre, la presión y el volumen así como el método exactitud deben ser medidos para ilustrar la relación entre la elasticidad y la viscosidad asociada con los procesos renales agudos.
Acceso abierto
Development of a MATLAB Environment Software for Simulation of Ultrasonic Field
(2014-05-05) Tronco-Gasparini, R. (Reynaldo); Nantes-Button, V. L. (Vera Lúcia da Silveira)
El estudio del campo acústico generado por un transductor ultrasónico es fundamental para su construcción y caracterización, ya que define cómo se comportará antes de ser construido. También define si realmente es factible para la aplicación a la que fue diseñado, y también puede sugerir modificaciones al proyecto, para que se comporte como se espera. En este trabajo un software fue implementado en MATLAB®, para la simulación computacional de los campos acústicos generados por los transductores ultrasónicos de diferentes configuraciones. Dos modelos fueran usados, Zemanek y Stepanishen. Transductores con el enfoque y apodización y medios con atenuación también pueden ser simulados. Para la simulación del modelo de Zemanek, se utilizó el método matemático de discretización y para el modelo de Stepanishen, se empleó una solución analítica para la respuesta impulsiva. Los programas desarrollados fueron agregados en un paquete computacional, llamado FSIM, y una interfaz gráfica fue creada. El usuario puede elegir entre algunas configuraciones del transductor y parámetros de simulación ya implementados; FSIM tiene una arquitectura modular y permite que otros módulos de simulación sean añadidos. Las simulaciones fueron validadas comparando resultados obtenidos previamente por otros trabajos de investigación del Departamento de Ingeniería Biomédica de la Facultad de Ingeniería Eléctrica y Computación de la UNICAMP y por los artículos clásicos de Zemanek y Lockwood y Willette.
Acceso abierto
Método para la evaluación del uso seguro de dispositivos médicos en el ambiente del hogar
(2014-05-05) Larée, D. (Dominique); Reyes, P. (Pablo)
The use of medical devices in the home environment, originally designed for hospital use has increased. Its use is complex and uncertain because of the inexperience of the lay user and the uncontrolled environment. The objective of this study is to evaluate the safety in the use of these devices through the creation of a conceptual model that identifies the risks that could arise for a group of lay users who operate them. Through a usability study and following the Grounded Theory methodology problems and errors were identified emerging through the home use of two different medical devices in order to create a conceptual model. The conceptual model obtained is reified as an evaluation tool that allows stakeholders to identify the most suitable medical device for a specific user, detecting the weaknesses that may lead to an unsafe use. The evaluation tool created effectively allows detecting risky characteristics, considering the particular situation of use.
Acceso abierto
Modelo paramétrico de la actividad eléctrica celular cardiaca estimado a partir de registros electrocardiográficos estándares
(2014-05-05) Illanes, A. (Alfredo); Sérandour, G. (Guillaume)
The main purpose of this paper is to relate cellular cardiac electrical activity with the cardiac electrical activity measured in only one electrocardiogram (ECG) lead, through a cellular action potential (AP) parametrical model. This is performed by relating known dynamics, which can be mathematically modeled, existing at a cardiac cell level, to dynamics which can be obtained from a standard ECG recording. The main cellular dynamic used for relating with the ECG is the one known as three dimensional cellular restitution curve, which relates the action potential duration (APD) with its preceding diastolic interval and with the APD of the preceding cardiac cycle. Similar restitution curves were found in ECG signals recorded under the isometric handgrip test by relating the QT interval with its preceding TQ interval and with the QT interval of the preceding cardiac cycle. Following this similarity, a parametrical restitution curve, derived from a three ionic current cellular AP model was fitted to the ECG restitution relation for AP model parameter estimation. This model is finally simulated by stimulating it with an impulse train of frequency similar to the heart rate of the tested subject. The results show that the restitution curve experimentally obtained from the ECG is similar to the one obtained from de AP model simulation. Moreover the simulated APD follows satisfactorily the QT interval time variation of the tested subject. This opens new perspectives for the analysis of cellular cardiac electrical activity from standard ECG recordings.
Acceso abierto
Traducción automática del lenguaje dactilológico de sordos y sordomudos mediante sistemas adaptativos
(2014-05-05) Betancur-Betancur, D. (Daniel); Vélez-Gómez, M. (Mateo); Peña-Palacio, J. A. (Juan Alejandro)
One of the main limitations of the people with hearing impairment is directly related to their difficulty interacting with others, either verbally or through auxiliary systems based on voice and audio. This paper presents the development of an integrated system of hardware and software for automatic fingerspelling sign language used by people with this type of disability. The hardware system comprises a glove which has a set of wireless sensors that capture a series of signals generated by the hand gestures, and a adaptive model based on the principles of neural computation, that allows recognition of a particular dactilologic language. Results from the integrated system showed great effectiveness in recognizing vowels from the dactilologic Spanish language. This recognition was influenced by the dimensionality reduction made by the neural model of the input signals representing movements, and the sensitivity factor that sets the limit between recognition and learning.
Acceso abierto
Construcción de matrices como sustitutos dérmicos: aplicación potencial en la regeneración de piel
(2014-05-05) Valencia-Serna, J. (Juliana); Pineda-Molina, C. (Catalina)
Wounds can cause loss of skin that limits the skin regeneration, making the treatment more difficult to address. The tissue engineering has developed skin substitutes that promote skin regeneration; however, it is imperative to find materials that allow fibroblast growth in order to find an appropriate skin substitute. The construction of tridimensional porous collagen and collagenhyaluronic acid matrixes crosslinked with 1-ethyl-3-(3-dimethyl aminopropyl) carbodiimide hydrochloride is presented in order to evaluate their potential use in skin regeneration therapies. Matrix porosity was evaluated. Degradation tests, human fibroblast adherence, viability and proliferation tests were performed. Matrixes had a uniform distributed porosity with mean diameters of 50 μm. Both collagen and collagen-hyaluronic acid (2:8 and 4:6) matrixes presented a progressive degradation rate with similar weight. After 24 hours under culture, the number of fibroblasts seeded on collagen matrixes were doubled, while the number of fibroblast seeded on collagen-hyaluronic acid matrixes remained similar. Even though porous structure and degradation rate of different types of constructed matrixes in this study are similar, collagen matrixes offer better adhesion and proliferation conditions for seeded fibroblasts in comparison with hyaluronic acid added matrixes, making them the best scaffold to be employed as a dermic substitute among the matrixes compared here.
Acceso abierto
Revisión de la literatura de las técnicas de medición para el estudio de la postura sedente
(2014-05-05) Delgado, A. (Adriana); Maradei, M. F. (María Fernanda); Espinel-Correal, F. (Francisco)
Aiming to find a measurement technique that allows studying the seated posture, we conducted the following systematic review. The search was made in specialized databases in the study area. The key words of the search included terms such as low back pain, sitting posture, pelvic tilt, among others. 2383 items were selected according to the review question proposed and these 228 from established inclusion criteria. They were found 17 items that allow you to identify the appropriate techniques for the stance study. The revision allowed proposing a guide for selecting a tool to evaluate the seated posture based on the benefits offered by the instrument to comply with the objectives of the study that you want to perform.
Acceso abierto
Modelo Arquitectónico para Interoperabilidad entre Instituciones Prestadoras de Salud en Colombia
(2014-05-05) Castrillón, H. (Helder); González Serrano, C. (Carolina); López-Gutierrez, D. M. (Diego Mauricio)
Nowadays governments, health services organizations and software developers face the need to improve the efficiency of information systems in health through information management and ICT implementation. One of the areas of interest is the development of interoperability profiles that allow exchange information and improve collaboration between different actors in the health system. The aim of this paper is to define and validate an architectural model of interoperability between information systems on IPS in Colombia. The model, grounded in Colombian legislation, suggests the use of SOA as a reference to define the software architecture and HL7 standard for the exchange of messages and clinical documents. Subsequently the model is evaluated by a group of professionals with experience in information systems development and piloted based on two interoperability scenarios in three IPS of Popayán. The model aims to provide a methodology for software modeling and development among health services organizations, improving the level of understanding and control over information transactions present in the delivery of services.
Acceso abierto
Fragilidad y comportamiento mecánico del esmalte dental
(2014-05-05) Rivera-Velásquez, C. A. (Camilo Alberto); Ossa, A. (Alexander); Arola, D. (Dwayne)
Dental enamel is one of the hardest and most mineralized tissues of the human body. This work studied the main mechanical properties of this hard tissue for third molars obtained from young Colombian patients. The hardness, apparent fracture toughness and brittleness of enamel were measured as a function of distance from the occlusal surface to the Dental Enamel Junction (DEJ) by means of microndentation techniques. It was found that the hardness measurements are highly dependent on the indentation load, with high values of hardness found when low loads were used. This behavior is explained by the size of the indentations which approached the size of single hydroxyapatite prisms for low load values, while for high load values the size of the indents covered several prisms. Overall, the mechanical properties measured on the enamel from young Colombians are close to the properties reported in the literature for young North American patients. Whether these similarities among young patients persist for older patients deserves further investigation.
Acceso abierto
Evaluación asistida por computador de la viabilidad espermática en humanos
(2014-05-05) Roa-Guerrero, E. (Edgar); Cortés-Mancera, F. (Fabián); Guerrero-González, N. (Neil); Cardona-Maya, W. (Walter); Morantes-Guzmán, L. (Luis)
Currently one out of six couples present fertility problems, with 50% of the cases being due to the male. Until now, seminal fluid analysis is the only test that evaluates a male’s fertility potential. Among other parameters, sperm viability is manually assessed, which contributes to high data variability as a result of expert subjectivity and eye-fatigue. The purpose of the present study was to develop and experimentally validate a flexible, programmable and modular-based computational tool for digital image processing, identification and classification of human sperm in a semen sample. The regions were extracted using Fisher discriminant analysis and classification methods by cluster analysis and particularly the K-means technique. The results show 87.9% accuracy in identifying living and dead sperm, 93.4% effectiveness in detecting live sperm and 76% effectiveness in detecting dead sperm, from a set of 110 images obtained from 14 individuals, compared with manual analysis according to the procedures established by the World Health Organization. This computational tool contributes to the objective analysis of human sperm, becoming an alternative to expensive commercial systems for computer-assisted semen analysis
Acceso abierto
Importancia de las frecuencias de resonancia del tracto vocal en la estimación de posiciones articulatorias
(2014-05-05) Sepúlveda, A. (Alexander); Casas -Gómez, D. M. (Diana Margarita); Castellanos, G. (Germán)
Acoustic-to-Articulatory inversion, which seeks to estimate an articulator position using the acoustic information in the speech signal, offers several potential applications in the field of speech processing. In this context, it is important to use acoustic parameters with the ability to increase the performance of acoustic-to-articulatory inversion systems. This paper analyzes the importance of formants as inputs to such inversion systems from an analytical and a statistical perspective. The former is based on an articulatory synthesizer that simulates the voice signal from the vocal tract. The statistical analysis is based on real data provided by an electromagnetic articulograph, for which we estimate the statistical association between acoustic features and articulator movement. As a measure of statistical association, the information measure is utilized. The results are tested on a neuralnetwork- based Acoustic-to-Articulatory inversion system. The use of formants as inputs led to an improvement of 2.2% and 2.8% in the root-mean-square error and correlation values, respectively.
Acceso abierto
Generación de señales simuladas de ECG abdominal a partir de un modelo abdominal 3D
(2014-04-30) Corona-Fraga, J. (Jaime); Gaitán-González, J. (Jatziri); Arias-Ortega, R. (Ronald); González-Camarena, R. (Ramón)
Abdominal ECG is one of the most promising monitoring techniques for fetal surveillance in the antenatal period, as it presents easy availability and allows the maternal and fetal monitoring simultaneously. However, separation of these signals is complicated and there is no standardized way to evaluate the effectiveness of separation algorithms reported in the literature. Based on the dipole model spread through the three-dimensional maternal abdomen, this paper proposes the implementation of a system for the generation of abdominal ECG signals with controllable characteristics simulating real conditions by interference, heart period variability, number of channels , electrodes location and fetal position. Using the developed system, 50 synthetic test signals were generated and compared with desired values. Results showed a correlation of 0.99 with respect to expected values in the signal interference ratio, with no significant differences in the regression (p>0.05); while the correlation coefficient was 0.87 for the signal to noise ratio, with significant differences below -20 dB (p<0.05) in the regression. In conclusion, the proposed system provides abdominal ECG signals showing similar conditions to those of real signals, and comprises a tool that ensures proper evaluation of separation algorithms of maternal and fetal ECG from abdominal ECG.
Acceso abierto
Metodología para dimensionamiento de mecanismo policéntrico de rodilla utilizando análisis de marcha y algoritmos genéticos
(2014-04-30) Amador, B. (Belkys); Torrealba, R. (Rafael); Rojas, M. (Maureen); Cappelletto, J. (José); Müller-Karger, C. (Carmen)
This research was aimed to develop a methodology for establishing the proper dimensions of a four-bar linkage prosthetic knee mechanism for maximum stability. Based on the fact that the stability of a four-bar knee during load-bearing is determined by the location of the instantaneous center of rotation (ICR) with respect to the ground reaction force (GRF) vector, a computational platform was developed to simulate the movement of the leg, the GRF vector and the position of the ICR of the mechanism. On one hand, a gait analysis was carried out on a subject with unilateral transfemoral amputation, from which the GRF, the knee flexion-extension angle and the kinematics of the lower limbs were determined. On the other hand, genetic algorithms (GAs) technique provided the dimensions and mechanism links configuration required to iterate with the platform on which, comparing the location of the GRF and the ICR in the sagittal plane, the functional dimensions of the mechanism were obtained. The polycentric knee mechanism was gauged successfully by ensuring knee stability during the initial contact and load response as well as the ability to initiate voluntary flexion toward late stance before the toe-off.
Acceso abierto
¿Disenso entre pares revisores? No se preocupe, que a fin de cuentas el editor siempre tiene la última palabra
(2014-04-30) Cruz, A. M. (Antonio Miguel)
All of us have at some point submitted a scientific paper for review with the idea of being published in a given journal. Often, the authors experience many barriers to success (achieving publication) when they submit articles for publication. These barriers depend on the quality of the writing itself, on the biases of the peer reviewers, the way you write your cover letter, and the way in which you address and respond to the observations (erroneous or not) emitted by peer reviewers and the editor of the journal. The purpose of this paper is to provide useful pieces of advice on how to publish articles that tackle issues in the health area in high impact journals in the area of Operations Research & Management Sciences.
Acceso abierto
Casos de innovación en salud en Colombia: retos y proyectos
(2014-04-30) Ruiz-Ibáñez, C. (Carlos)
Acceso abierto
Entrevista al director del clúster de servicios de medicina y odontología de Medellín, Carlos Enrique Cárdenas Rendón
(2014-04-30) Valencia-Díaz, E. (Edison)
Acceso abierto
Modelado y simulación de un robot para cirugía endoscópica transluminal
(2014-04-30) Mosquera-Leyton, V. H. (Víctor Hugo); Vivas-Albán, O. A. (Oscar Andrés); Rengifo-Rodas, C. F. (Carlos Felipe)
This article presents the design of a new robot for translumenal endoscopic surgery. This type of surgery, evolved from laparoscopic surgery, allows the access into the abdominal cavity of the patient through natural oriﬁ ces such as the mouth, urethra, anus or vagina, and from there reaches the area of the surgical intervention. This procedure has many advantages over laparoscopic surgery. The designed robot has nineteen degrees of freedom and is moved with a joystick device and controlled by a computer torque control. Simulation shows low cartesian errors as well as accurate movements at the end effector.
Acceso abierto
Apropiación social e investigación participativa en ingeniería en rehabilitación
(2014-04-30) Villa-Moreno, A. (Adriana); Correa-Restrepo, M. L. (Margarita Lucía); Acosta-Ramírez, S. (Stefanía); Guarín-Grisales, A. (Álvaro)
One of the main goals of rehabilitation engineering is improving the quality of life of people with disabilities through developing solutions for their speciﬁ c needs. When participatory methodologies for research and design are applied, the resulting solutions show advantages such as products that better address the needs of the community, solutions that are better accepted by the community, and the identiﬁ cation of potential sources and niches for innovation. In addition, participatory methodologies provide beneﬁ ts that are not only associated with the generated results and products but with the processes themselves. When research processes are inclusive and promote authentic participation a higher social impact can be obtained. This paper proposes a methodological approach for the development of habilitation and rehabilitation products that allows the convergence of participatory research tendencies, design tendencies and the voice of the community that claims for co-participation. This approach also incorporates strategies for the social appropriation of knowledge. Examples, barriers, difﬁ culties, challenges and recommendations for conducting research with a focus on participation are also presented. The reﬂ ections herein presented may also be applied to other ﬁ elds.
Acceso abierto
Preguntas y respuestas sobre medicina regenerativa
(2014-04-30) Zapata-Linares, N. (Natalia); García-Quiroz, F. (Felipe)
Regenerative Medicine seeks to develop strategies to restore damaged tissues. The recent boom of this research ﬁ eld and its potential for the treatment of a wide variety of diseases —such as neurodegenerative, hepatic and cardiac, or skin burns and various traumas— demands an ongoing analysis of the most recent investigations, their impact, the associated ethical debates, as well as the research horizon in the coming years. To answer these and other questions we reviewed the most important advances reported throughout the year 2011 and consulted the opinion of a regenerative medicine expert, profesor Felipe Prosper Cardoso from the University of Navarra in Spain. Despite the signiﬁ cant progress in the laboratory regarding the derivation of autologous cells (whether differentiated or pluripotent) and the development of biomaterials that facilitate regeneration, the clinical translation of regenerative medicine therapies is still incipient and constitutes a grand challenge for researchers in this fascinating ﬁeld
Acceso abierto
Estimation of vibration and force stimulus thresholds for haptic guidance in MIS Training
(2014-04-30) Mesa-Múnera, E. (Elizabeth); Ramirez-Salazar, J. (Juan); Boulanger, P. (Pierre); Bischof, W. (Walter); Branch, J. (John)
El presente artículo muestra los resultados de una investigación para determinar los umbrales de mínima percepción ante estímulos de fuerzas y vibraciones aplicados durante la realización de un movimiento simple y utilizando el mismo dispositivo háptico. El modelo utilizado se derivó del bien conocido método de Up-Down Transformed Response Rule donde la retroalimentación fue variada en términos de la magnitud de la fuerza y de la amplitud de la vibración. Se demostró que la percepción de vibración fue alrededor de quince veces más pequeña que el umbral de fuerzas y se compararon los resultados con trabajos previos para diferentes tareas, conﬁ guraciones experimentales y distintos dispositivos. Se concluyó que el tipo de tarea afecta signiﬁ cativamente el umbral de detección humano tanto para retroalimentaciones de fuerzas como de vibraciones. Además es fundamental considerar estos valores en el diseño de nuevos sistemas de guiado hápticos para el entrenamiento de habilidades requeridas en Cirugías Mínimamente Invasivas (MIS por sus siglas en Ingles).